Pulse interval time division system



4 Sheets-Sheet l P. W. BORGESON PULSE INTERVAL TIME DIVISION SYSTEM June 23, 1953 Filed sept. 12, 195o .NDQSO .Umm ON /NVENTQR PAUL. W BORGESON @Y @am Q ATTORNEY,

June 23, 1953 v 2,643,330

P. W. BORG ESON PULSE INTERVAL TIME DIVISION SYSTEM Filed Sept.` 12, 1950 4 Sheets-Sheet 2 VOLTE VOLTS VOL'IS I To @PAC/Tore 60 2V-TM To capAc/Tofz 78 h F/zoM COUNT Dow/v I BLDCKING 056/1.-

LATURAND DI ODE 34 Hna/L W @masso/v L 1 Y AT REV l l l l I E /NVENTOR l l l June 23, 1953 P. w. BoRGEsoN 2,643,330

PULSE INTERVAL TIME DIVISION SYSTEM Filed Sept. l2, 1950 4 Sheets-Sheet 5 FROM MASTER smak/N6 osc/LLATo/z /8 /NVENTOR Bv @LA A-r o/NEY June 23, 1953 P. W. BORGESON PULSE INTERVAL TIME DIVISION SYSTEM 4 Sheets-Sheet 4 Filed Sept. l2, 1950 cou/vr oowIv MVS/2 27 AMPLIFIER 20, MASTER BLOCK/N6 oscILLAoR /8, AMPLIFIER TUBE AND BLOCK/N6 oscILLAToR CIRCUIT I7 F'IG, 6

/Iw/ENTR` PAUL W. BORGEsoN ev @IM 3 Patented June 23, 1.953

PULSE INTERVAL TIME DIVISION SYSTEM Paul W..Borg,eson,` Little Falls, N. J., assignor to. Raytheon Manufacturing Company, Newton, Mass., a corporation of Delaware Application September 12, 1950, SerialfNo. 184,422

(Cl. Z50- 27) 4 Claims.

This invention relates to automatic time'di` vision of signal pulse intervals.

For applications such as pulse time communication systems, television transmitters and receivers, radar ranging relays, time measurements and the like, it often becomes desirable to divide a relatively constant period between incoming pulses into a selected number of sub-periods.

Pursuant to the present invention such a time-division system is provided which also succeeds in incorporating particularly desirablev characteristics for a system of this type. Among them are the ability to retain for a lengthv of time previous information regarding the incoming period, ability to work through a relatively large amount of spurious input information, automatic control for changes in time of occurrence and period of the incoming information, equality of sub-periods, ability to synchronize automatically, and easily made adjustments.

These and other objects, features and advantages of the invention will become more apparent from the following description taken in connection with the accompanying drawings wherein:

Fig. 1 is a partiallyV block and partially schematic diagram of one embodiment of the invention,-

Fig. 2 is a graph of exemplaryY pulses and gating potentials occurring n the.v embodiment in Fig. 1 for more clearly illustrating the operation thereof;

Fig. 3 is a schematic view of an alternate construction for a portion of the embodiment in Fig. l;

Fig. 4 is a circuit diagram ofv suitable count down multivibrator, cathode. follower and differentiating circuits for use in Fig. 1;

Fig.v 5 is a circuit diagram of a suitable count down blocking oscillator and diode circuit for use `in Fig. 1; and l Fig..- 6 is a circuit diagram of suitable amplier, master blocking oscillator, and amplifier tube and master blocking oscillator circuits i Figi. 1.

Referring to the drawings, the present'bembodifm'ent of the invention, forpurposes Vof clarityl in illustration, is particularly adapted., to

divide' the period: I0, between. input pulsesv IZYinto" thirtysix equal divisions. However, WhereV d*- sired, the system to be hereinafter described may be used equally well for other time division rates by suitable variation of circuit constant.

If the interval I0 between pulses I2 is 720 microseconds, division into thirty-six equal intervals will result in a desired twenty microsecond interval I4 between output time division pulses I6 from an output amplifier tube and blocking oscillator circuit I1. To obtain this output pulse interval, the output circuit l'l is triggered .by a free-running frequency controlled oscillator, such as a free-running blocking oscillator I8, which is used as the master and preferably having a free-running period approximately that of the selected period I4. Ihe master blocking oscillator I8 has its oscillation frequency controlled by the voltage from a conventional amplifier circuit 20 which is determined by the Voltage at point 22 from a charge onv capacitor 24 when switch 26 is open. Exemplary circuits I1, I8 and 20 are shown and described with reference to Fig. 6. However, other circuit arrangements may be used equally well. The charge on the capacitor 24 is, in turn, made to depend on two primary factors, namely, the pulse rate from the master blocking oscillator I8 and the period IIJ of the synchronized pulses I2. The pulse rate is made to influence the charge on the voltage control condenser 24 by causing the triggering or operation of a suitable count down circuit 21, such as a bistable multivibrator which may be similar to the multivibrator illustrated and hereinafter described with regard to Fig. 4, The multivibrator 21, in turn, causes square wave pulses 28 at half the rate of pulses from the master blocking oscillator 26 to feed a suitable cathode follower circuit 30 as, for example, illustrated and described with regard to Fig. 4. The square wave is then differentiated at the circuit 30 and applied to series count down circuits 32 and 34 whichmay be step down diode circuits and blocking oscillators, as illustrated and described with reference to Fig. 5, in this instance with a circuit constantto give a three to one count down ratio for each. Triggering pulses 44 will appear in output line 36 from the count down circuit 34v at one eighteenth, the rate of pulses generated by the,n master blocking oscillator I8 and', having an interval of eighteen times the interval between pulses I6. These pulses trigger a suitable gating circuit, such as a bistable multivibrator 38, which effects a further count down to a gating cycle of thirty-six times the interval between pulses I6. The multivibrator 38 may be similar to that shown and described with reference to Fig. 3. Lines 4Il and 42 may each, respectively, be from an anode of the two operating multivibrator tubes contained in such multivibrator circuit. Thus each time a pulse 44 (Figs. l and 2) occurs in line 36 the multivibrator 38 is triggered to operate so as to cause a gating potential pulse picture in lines 48 and 42, as shown by curves 46 and 48 (Fig.l 2), respectively. blocking oscillator 50 in a manner such that any pulse 52 appearing in line 54 from a suit" able thyratron trigger circuit, 56 Vduringv the positive portion of the gating pulse '46will apf pear as positive pulse 58 through condenservl.

at the anode 6l of a unidirectional curren't'valve 82, such as a diode. The diode .62 is suitably biased through a resistance 64, as by a battery,

66, so as to normally maintain diode 62 nonconductive. The appearance of the positive pulse 58 through condenser 6|] overcomes this bias and causes conduction in diode 62 andthrough the adjustable'resistance 68 which is connected between cathode 69 of diode 62 to charge the condenser 24 with the side 22 of the condenser 24 positive with respect to ground. Uniformity of the sizeof pulses 52'is insured by the thyratron trigger circuitl 56. However, the amount of charge which the pulse 58 will place on the condenser Y24 will depend on where alongv the gating curve 46 (Fig. 2) Ait occurs. For example, if it occurs along a peak portion 'I8 (Fig. 2), it will have a maximum charging effect. Along the slope 'I2 it will have a progres'-` sively diminishingcharging eiect with a minimum charging effect along the minimum por-V tion i4 of the curve 46. v

The line 42 is coupled to agated blocking oscillator 'I6 at which pulses' 52 from the Athyratron trigger circuit also appear through line 54. IThe output line from the blocking oscillator 'I6 to a condenser 'I8 is taken in a manner that the positive pulse 52 will cause a negative pulse 88 to appear at the condenser 18. The charging eiect of the negative pulse 80 appearing at the condenser 'I8 is dependent, as in the case of pulse 58, upon its position valong the gating potential curve 48 (Fig. 2). `88 will have a maximum negative charging eect along the top portion 82 of gating curve 48, and a minimum negative charging eiTect along the bottom portion 84 of gating curve 48. The negative charging eiTect of the pulse 80 will vary between these maximum and minimum values at the slopes 86 of gating'V curve 48. An exemplary gated blocking oscillator arrangement suitable for this purpose is hereinafter described with reference to Fig. `3.

The negative pulse 80 appears through the condenser 'I8 at the cathode 88 (Fig. 1) of al unidirectional current valve BIL-such as a diode. Anode S2 of the diode 90 is connected through anadjustable resistance 94 to Athefside 22 of condenser 24. The diode 90 is maintained normally nonconductive by a suitable bias, as fromf duct -thereby'charging the"fc'apa'citor- 24 'nega'- Line 40 is coupled to a gated .1.5

The pulse 4 tively, as explained above. The size of the negative charge on the capacitor 24 effected by the pulse 88 may be further controlled by the adjustment on resistor 94.

It will be noted that, for each pulse 52 from the thyratron trigger circuit 56 and therefore for each input pulse I2, a positive charging pulse 58 and negative charging pulse 80 will appear to charge the control capacitor 24, as explained above. As already explained, the effective charging amplitudes of these pulses will be dependent upon their position along the gating `potential curves 46 and 48. It should also be noted that l their respective charging amplitudes vary in- ,'jportion 82 ofthe gating curve 48, the pulse 58 Vhas a minimuml positive charging amplitude since it will occur along the bottom portion 'I4 'of curve 46,. Thus here the net charge on capacitor 24 is negative. A negative charge on capacitor 24 causes the potential at point 22 to go negative by the same amount. This negative-going potential is amplied by thev amplifier 20 to a suitable level and appearsl at the master blocking oscillator` I 8 causing an increase in its pulse rate. 'The pulses 28 and 44 will therefore occur more frequently and the period of the gating pulses 46 and 48 will thereby be l 'shortened gating period is to shift the relative position of the input pulses I2 to the left or right, respectively, along the gating curves 46 and 48.

.'The variableresistances 68 and 94 are preferably mechanically connected so that the resistances Vare essentially equal at all times. The voltage obtained from either battery 66 or 94 may be varied to equalize the effects of the pulses 58 and 80 when they occur at point 96. Resistances 68 and 94 are varied to obtain the optimum comprise between noise immunity and time of response to change in the incoming signal I2.

When the period 98 of the gating potential curves 46 and 48 is exactly equal to the interval I0 between input pulses I2, the pulses I2 will occur at a time relation coinciding with the points 96 where charging pulses `58l and' 80 neutralize each other and master blocking oscillator is oscillating`v so as toproduce pulses I6 at exactly thirty-six times the rate of pulses I2.

Automatic compensation also occurs for changes in the period I0 of input pulses I2. For example, if the incomingperiod I0 increases slightly, the'pulses 58 and 80 will occur somewhat later with respect to the multivibrator gating curves 46v andn 48',y andwill change the charge-on-capacitor"24 in small steps to reachv the correct control -'v'oltag'e to produce the exact i 1 thirtysixl output pulses: 'I 6 'within' this increased interval.: .l

pulses 52 and there-r It is thus seen that an automatically selfcorrective servo loop is achieved in Fig. 1 whereby time division ofthe interval between the input synchronized pulsesY I2 is obtained.

Other time division rates may b e obtained simultaneously from the apparatus in Fig. 1 by adding additionalV blockingv oscillators and |02 triggered from suitable amplifier tubes connected to cathode follower and differentiating circuits |04 and 3 0, respectively. The circuit |04 may also be similar to that hereinafter described with reference to Fig. 4. By connecting the cathode follower circuit |04 tothe anode of one ofthe operative tubes of the multivibrator 21, and the cathode follower 30l to the anode of the other of the operativev tubes of the multivibratorl 2l, forty microsecond interval out,- puts |06 and |555 differing from each other by twenty microseconds are obtained.

The cathode followers in circuits |04 and 30 areV inserted primarily to isolate the output triggered blocking oscillators |00 and |02 from interfering. with operation of the multivibrator 2l.

In general operation, since the natural period, that is, when no charge is on the condenser 24, is approximately thirty-six times. that of the synchronized pulses |2, the pulses 58` and 80 will, from the start, occur along. the slopes '|2 and 86, respectively. The corrective action will therefore, in general, be conned to the slopes l2 and 86 in seeking out they neutral point 9B. The amount of seeking and speed of corrective response may be controlled by varying circuit constants in accordance with conventional servo mechanism principles. v

Since the diodes 62 and 9|) feeding capacitor 24 are biased well below conduction unless a pulse 58 and 80, respectively, is applied, the discharge time of the capacitor 24 will be determined by parasitic circuit elements, such as capacitor leakage, gas currents and the like. Thus the control voltage across the capacitor 24 will change relatively slowly under conditions of loss of incoming information.

Where such operating conditions as high ternperature variations occur to disturb the constancy of operation of gas-filled tubes, as the thyratron in the thyratron trigger circuit B, it may be replaced by a blocking oscillator ||2 triggered through an amplifier tube ||4, Fig. 3. In this case, the blocking oscillator ||2 replaces not only thyratron trigger circuit 56, but also the gated blocking oscillators 50 and '16. To accomplish this, one end of the third and fourth windings lit and H8, respectively, of the transformer |20 of the blocking oscillator ||2 is connected to the positive terminal of a potential source, as battery |22. The negative terminal |24 may be connected to ground. The other ends of windings HS and ||8 are led through voltage divider resistances |26, |28 and I 30, |32, respectively, to anode |34 of operating tube |35 in a multivibrator count down circuit |36, which may be the multivibrator circuit 38 (Fig. 1). Lines |38 and |40 are led from suitable pickoff points between resistances |30, |32 and |26, |28, respectively, to capacitors E0 and 18 (Fig. l), respectively, in the unidirectional charging circuits for control capacitor 24. Thus when an input pulse I2 occurs through capacitor |42 at grid |43 of the triode H4, it causes a progressive build-up in the transformer |20 due to feedback of the secondary winding |45 so that the blockpulse |48 through winding 8 and resistance |30fin linev |38. In similar manner, negativegoing. pulse |50 is induced through winding H6 and resistance |25 in line |43. The charging effect of the pulses |48 and |50 on control capacitor 24 will depend upon the gating potential in lines |38 and |40 due to the operation of the multivibrator |35.

When the operating tube |35 of the multivibrator |36 is conductive, the potential at anode |34, and therefore in lines |38 and |50, drops. Its eifect is to increase the negative charging effect of pulse |50 and reduce the positive charging eect of pulse |48. The charge on control condenser 24 will be caused to go negative. In- Versely, when the operating tube |35 is nonconductive, the potential of anode |34, and therefore lines |33 and Utd, rises. The result is a decrease in negative charging effect of the negative pulse |50, and the positive charging effect of pulse |48 is increased. In such case, the charge on the control condenser will be caused to go positive. Along the gating slope between these two extremes, progressively decreasing charging effects occur until a neutral charging point is reached where no resulting charging effect occurs. The potential picture in` lines |43 and |59 will be similar to that of curve 4S with the neutral point just mentioned being. preferably at point 9% (Fig. 2).

Since the multivibrator |36 is of the bistable type, its period is determined by the pulses 44 from the count down blocking oscillator and diode circuit. 34. Each time a pulse 44 appears in line |52, the operating tube |35 will be caused alternately to be made conductive and nonconductive in opposite relation to the other operating tube |52 of the multivibrator |35. Automatic seeking of the neutral point 96 and servo operation will be similar to that explained with regard to Fig. l.

As hereinabove mentioned, the gated blocking oscillators 59 and iii in the embodiment in Fig. 1 may be similar to the blocking oscillator H2, Fig. 3. Also, count down gating multivibrator 38 may be similar to the multivibrator |36, Fig. 3. In the embodiment in Fig. l, hcwever, instead of coupling the third and the fourth windings |||i and |||l, respectively, of the pulse transformer |20 both to the anode |34 of the multivibrator |36, only one of the windings, as winding H8, is coupled through resistances it and |32 to the anode |34. Such arrangement would represent the gated blocking oscillator 5@ in Fig. 1. For the circuit 'i6 another blocking oscillator similar to ||2 may be used having in this instance its third winding H5 connected through resistances |26 and |28 to anode |54 of the operating tube |52 of the multivibrator |36. Thus when the potential at anode |34, and therefore in output line |38, is low, the potential at anode |54, and therefore in output line Idil, will be high and the circuit will otherwise function as explained with regard to blocking oscillators 59 and it in Fig. l.

Suitable count down multivibrator 2l and cathode follower and differentiating circuits 30 are illustrated in Fig. 4. In the multivibrator circuit 2l, a twin triode tube |55 is used to provide the two operating triodes |58 and |50 with a common cathode |62 connected through resistance-- |64 to ground, and tol which is also ccnnected the input line |66 from the master blocking oscillator I8. The anodes |68 and |70 are led through resistances |12 and |14 to a common positive terminal of a power source, such as battery 116, the negative terminal of which is connected to ground. Feedback is provided from anode |68 of triode |60 through a grounded capacitive resistive network |18 to grid |80 of triode |58. Feedback for anode is provided through another grounded capacitive resistive network |82 to grid |84 to triode |60. Circuit constants are such that the operation will be stable with either of triodes 69 or |58 conducting. Each time a pulse |86 appears in line |66 from the master blocking oscillator I8, it causes a switching action which extinguishes the triode which is conducting and results in conduction in the triode which was nonconductive. This switching action produces in line |88, running from anode |68 to the cathode follower circuit 30, the square wave pulse 28. The square wave pulse 28 represents two pulses |86, the rst pulse |66 forming the leading edge 190 of the square wave pulse 28, and the second pulse |86 forming 'the trailing edge |92 of the square Wave pulse 28.

Line |88 is connected through a capacitor |94 to the grids |96 of a twin triode |98 having a common cathode 200 connected through resistance 232 to ground. The common cathode 200 is connected to a differentiating circuit formed by capacitance 204 and grounded resistance 206 in output line 268. The grids |96 of the twin triodes |98 are also connected through a resistance 2I0 to the positive terminal of a power source, such as battery 2|2, whose negative terminal is grounded. The grids |96 are also grounded through a resistance 2 I4. Anodes 2 I5 of the twin triodes |98 are also connected to the positive terminal of battery 2|2.

The square wave pulse 28 in line |88 appears through capacitor |94 at grids |96 causing a corresponding square wave pulse picture at the common cathodes 200. This pulse is `differentiated by the capacitor 204 and grounded resistance 286 so as to appear in output line 208 as a positive pulse 218 corresponding to the leading edge 96 of pulse 28 and a negative pulse 220 corresponding to the controlling edge |92 of square wave pulse 28.

The cathode follower and diiferentiating circuit 36, as described with regard to Fig. 4, is also suitable for use directly in the cathode follower and differentiating circuits |04 in Fig. 1.

A suitable count down blocking oscillator and diode circuit for use in circuits 32 and 34 of Fig. l is illustrated in Fig. 5. It consists essentially of a conventional blocking oscillator circuit 222 and a diode step charging circuit 224. The blocking oscillator circuit has a twin triode 225` having a common cathode 228 connected to ground. Its anode 230 is connected through the primary winding 232 of a pulse transformer 234 and through a resistor 236 to the positive terminal of a power source, such as a battery 238, whose negative terminal is connected to ground. A point between resistor 236 and the primary winding 232 is connected through a capacitor 240 to ground. Grids 242 of the twin triode 226 are connected through secondary winding 244 of pulse transformer 234 and through capacitors 246 and adjustable resistance chain 248 to the negative terminal of a power source, such as battery 258, having its positive terminal connected to ground. Grids 242 'are also connected through a condenser 252 toa point 254 between capacitors 246 and adjustable resistance chain 248. Point 254 is connected through capacitor 256 to ground. Diode 258 is connected with its cathode 260 to a point between capacitors 246 and winding 244 of pulse transformer 234. Anode 262 of diode 258 is connected to a point between capacitor 252 and point 254. The positive pulse 2I8 appearing from line 208, Fig. 4, through capacitor 264 at anode 262 will cause the diode 258 to conduct and thereby charge the capacitors 246. The negative pulse 220 will have no eect on diode 258 and therefore will have no eiect in the charge on condenser 246. Each time a pulse 2I8 occurs, it will charge the condenser 246 by a small amount in stepped fashion, as shown by curve 266. The potential setting at the adjustable resistance chain 248, due to battery 250, is such that, when the peak 268 is reached in each third charging step, the potential at grid 242 triggers a blocking oscillator 222 causing it to produce an output pulse 210 in line 212 from the third and fourth windings 214 and 216, respectively, in the pulse transformer 234.

The operation just described is where the circuit in Fig. 5 is used as the count down blocking oscillator and diode circuit 32. Where the circuit in Fig. 5 is used for the count down blocking oscillator and diode circuit 34, the input pulses to circuit 34 will be the pulses 210, Fig. 5, which will appear at the capacitor 264. In that case, the output pulses in line 212 will be the positive pulses 44 which are then applied through line 36 to the count down gating multivibrator circuit 38. A suitable amplifier circuit 2), master blocking oscillator circuit I8, and amplier tube and blocking oscillator circuit I1 are shown in Fig. 6. The potential at point 22 from 'the capacitor 24 is made to appear at grid 236 of a pentode 242 having a suppressor grid 284 tied back to a cathode 286 which is connected through a parallelconnected capacitor 268 and resistor 290 circuit to ground. Screen grid 292 of the pentode 284 is connected to the positive terminal of a potential source, such as battery 234, whose negative terminal is Connected to ground. Anode 298 of the pentode 282 is connected through resistance 360 to the positive terminal of the battery 294 and through a variable resistive and capacitive networkv 382 and primary winding 304 of a pulse transformer 386 to grids 308 in twin triodes 3I0 of the master blocking oscillator circuit I8. Common cathodes 3|2 of the twin triodes 3|0 are connected through resistors 3I4 and 3I6 to ground. Output line 3|8 leading to the count down multivibrator circuit 21 is taken from a point between the voltage divider resistances 3|4 and 3I6. The common cathodes 3|2 of the twin triodes 3|@ are also connected through a capacitor 320 to grid 322 of an amplifier triode 324 in the twin triode tube 326 also containing the triode 328 in the amplifier tube and blocking oscillator circuit I1. The triode 324 provides the amplifier tube referred to in the title of the circuit Anodes 330 of the twin triode tube 3|!! are connected through secondary 332 of the pulse transformer 356 and through a resistor 334 to the positive terminal of a power source, such as a battery 336, having its negative terminal connected to ground. A point between the resistor 334 and transformer secondary 332 is connected through series-connected capacitors 338 and 340 and kthrough primary winding 342 of a pulse transformer 344 in the blocking oscillator circuit I1 to the anodes 346 and 348 of the triodes 324 and 328, respectively, in the twin triode tube 326. The point between capacitors 338 and 340 is grounded, and a point between capacitor 340 and the primary winding 342 of the pulse transformer 344 is connected through resistor 350 to the positive terminal of a potential source, such as battery 352, the negative terminal of which is connected to ground. The twin triodes 326 have a grounded common cathode 354, which is also connected through capacitor 356 and secondary 358 of the pulse transformer 344 to grid 350 of the triode 328. A point between secondary winding 358 and capacitor 356 is connected through voltage divider resistances 352 and 364 to the negative terminal of a power source, such as a battery 366, the positive terminal of which is connected to ground. The common cathode 354 is also connected through a capacitor 35B to a point between voltage divider resistances 352 and 364. Third and fourth windings 310 and 312 of the pulse transformer 344 have one of their respective ends connected to a common ground and the other of their respective ends connected to the Ioutput line 314 providing the twenty microsecond output shown in Fig. 1 at the amplifier tube and blocking oscillator l1.

In operation, the potential at point 22, and therefore at control grid 280, is amplied to a suitable level by amplier tube 282 as determined by the setting on the adjustable resistance chain in the capacitive resistive network -302 so as to control the rate of oscillation of the free-running oscillator I8. Oscillation of the free-running oscillator I8, as controlled by this potential, causes pulses 315 to appear in the cathode line 312 at a rate determined by this controlled potential. The pulses 315 appear through resistor 3i4 in output line 318 and through output line 3|8 at the count down multivibrator` 21 to cause the multivibrator 21 to operate as described above. Pulses 31;` also appear through capacitor 320 at grid 3220i the amplifier tube 324 so as to trigger the amplier tube and blocking oscillator circuit l1 causing it to emit pulses I6 through line 314 as described with regard to Fig. 1.

The amplier tube and blocking oscillator I1 illustrated in Fig. 6 is also suitable for use directly in the amplifier tube and blocking oscillator circuits 100 and l02. When used in the circuits |00 and |02, the amplier tube 324 will be triggered by the positive pulses 2|8 from the cathode follower iand differentiating circuits |04 and 30, respectively, as described in connection with Fig. 4.

This invention is not limited to the particular details of construction, and processes described, as many equivalents Will suggest themselves to those skilled in the art. It is accordingly desired that the appended claims be given a broad interpretation commensurate with the scope of the invention within the art.

What is claimed is:

1. A system for dividing the interval lbetween electrical input pulses of substantially constant interval comprising means for producing electrical output pulses at a rate determined by a control voltage, a capacitor in voltage control relation to said output pulse producing means, two unidirectional current means responsive to said input pulses for charging said capacitor, one of said current means for charging said capacitor positively and the other of said current means for charging said capacitor negatively with respect to a selected reference value, la gated blocking oscillator coupled to each of said current means and in pulse responsive relation to said input pulses, and means responsive to said output pulses for gating said blocking oscillators in la manner to vary the charge of said input pulses on said capacitor in accordance with the deviation from a selected ratio of the nate of said output pulses to said input pulses and thereby effect a return of said ratio to the selected value.

2. A system for dividing the interval between electrical input pulses of substantially constant interval comprising means for producing electrical output pulses at a rate determined by a control voltage, a capacitor in voltage control relation to said output pulse producing means, two unidirectional current means responsive to electrical pulses for charging said capacitor, one of said current means for charging said capacitor positively and the other of said current means for charging said capacitor negatively with respect to a selected reference value, a gated blocking oscillator coupled to each of said current means, a thyratron trigger circuit responsive to said input pulses and in pulse producing relation to said gated blocking oscillators for producing said electrical pulses for said unidirectional current means, and means responsive to said output pulses for gating said blocking oscillator and thereby controlling the resulting charge on said capacitor from said current means in accordance with the ratio of the rates of said output and input pulses.

3. A system for dividing the interval between electrical input pulses of substantially constant interval comprising means for producing electrical output pulses at a rate determined 'by a control voltage, a capa-citor in voltage control relation to said output pulse producing means, two unidirectional current means ior charging said capacitor, one of said current means for charging said capacitor positively and the other of said current means for charging said capacitor negatively with respect to a selected reference value, a

blocking oscillator responsive to said input pulsesfor causing charging pulses in'said unidirectional current means, and means responsive to said output pulses for gating said blocking oscillator and thereby controlling the resulting charge on said capacitor from said current means in accordance with the ratio of the rates of said output and input pulses.

4. A system for dividing the interval between electrical input pulses of substantially constant interval comprising means for producing electrical output pulses at a rate determined by a control Voltage, a capacitor in voltage control relation to said output pulse producing means, two unidirectional current means for charging said capacitor, one of said current means for charging said capacitor positively and the other of said current means for charging said capacitor negatively with respeet to a selected reference value, a blocking oscillator arranged to cause for each of said input pulses a positive charging pulse in said positively charging current means and a negative charging pulse in said negatively charging current means, and means responsive to said output pulses for gating said blocking oscillator and thereby controlling the resulting charge on said capacitor from said current means in accordance with the ratio of the rates of said output and input pulses.

PAUL W. BORGESON.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 2,277,000 Bingley Mar. 17, 1942 2,450,360 Schoenfeld Sept. 28, 1948 2,490,500 Young Dec. 6, 1949 

